Natural inhibitors of germination are various substances in the seed or in nature, such as "blastocholines", for example, lactones selected from scopoletin, parascorbic acid, daphnetin, coumarin; phenol derivatives, such as phloridzin, chlorogenic acid, juglone, cinnamic acid, coffee acid, ferulic acid, mustard oil glycosides, such as allyl-, and beta-phenylisothiocyanate; aldehydes selected from citral aldehyde cinnamic aldehyde, salicyl aldehide and benzaldehyde and the newly discovered abscisic acid.
Germination is usually controlled in practice by using thiourea, which stimulates germination and by using coumarin, which inhibits germination.